package com.itheima2.work5;

public class Yuanpan {
    public static void main(String[] args) {
        int feibo = getFeibo(5);
        System.out.println(feibo);


    }
    public static int getFeibo(int month) {
        if (month == 1) {
            return 1;
        }
        return getFeibo(month - 1)*2+1;
    }
}
